|
Fluorotelomer
Fluorotelomers are fluorocarbon-based oligomers, or telomers, synthesized by telomerization. Some fluorotelomers and fluorotelomer-based compounds are a source of environmentally persistent perfluorinated carboxylic acids such as PFOA and PFNA, while others are under extended investigation. Types There are many broad categories of fluorotelomers: * Fluorotelomer alcohols (FTOH) * Fluorotelomer ethoxylates (FTEO) * Fluorotelomer fumarates * Fluorotelomer methacrylates (FTMAC) * Fluorotelomer sulphonates (FTS) Production In the radical telomerization of fluorotelomer molecules, a variety of fluorinated alkenes can serve as unsaturated taxogens including tetrafluoroethylene, vinylidene fluoride, chlorotrifluoroethylene, and hexafluoropropene. However, many fluorotelomers, such as fluorotelomer alcohols, are fluorocarbon-based because they are synthesized from tetrafluoroethylene. In addition to alcohols, synthetic products include fluorotelomer iodides, olefins, and acryla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorotelomer Ethoxylate
Fluorotelomers are fluorocarbon-based oligomers, or telomers, synthesized by telomerization. Some fluorotelomers and fluorotelomer-based compounds are a source of environmentally persistent perfluorinated carboxylic acids such as PFOA and PFNA, while others are under extended investigation. Types There are many broad categories of fluorotelomers: * Fluorotelomer alcohols (FTOH) * Fluorotelomer ethoxylates (FTEO) * Fluorotelomer fumarates * Fluorotelomer methacrylates (FTMAC) * Fluorotelomer sulphonates (FTS) Production In the radical telomerization of fluorotelomer molecules, a variety of fluorinated alkenes can serve as unsaturated taxogens including tetrafluoroethylene, vinylidene fluoride, chlorotrifluoroethylene, and hexafluoropropene. However, many fluorotelomers, such as fluorotelomer alcohols, are fluorocarbon-based because they are synthesized from tetrafluoroethylene. In addition to alcohols, synthetic products include fluorotelomer iodides, olefins, and acr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorotelomer Methacrylate
Fluorotelomers are fluorocarbon-based oligomers, or telomers, synthesized by telomerization. Some fluorotelomers and fluorotelomer-based compounds are a source of environmentally persistent perfluorinated carboxylic acids such as PFOA and PFNA, while others are under extended investigation. Types There are many broad categories of fluorotelomers: * Fluorotelomer alcohols (FTOH) * Fluorotelomer ethoxylates (FTEO) * Fluorotelomer fumarates * Fluorotelomer methacrylates (FTMAC) * Fluorotelomer sulphonates (FTS) Production In the radical telomerization of fluorotelomer molecules, a variety of fluorinated alkenes can serve as unsaturated taxogens including tetrafluoroethylene, vinylidene fluoride, chlorotrifluoroethylene, and hexafluoropropene. However, many fluorotelomers, such as fluorotelomer alcohols, are fluorocarbon-based because they are synthesized from tetrafluoroethylene. In addition to alcohols, synthetic products include fluorotelomer iodides, olefins, and acrylate mon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perfluorooctanoic Acid
Perfluorooctanoic acid (PFOA; conjugate acid, conjugate base perfluorooctanoate; also known colloquially as C8, from its chemical formula C8HF15O2) is a perfluorinated carboxylic acid produced and used worldwide as an industrial surfactant in chemical processes and as a chemical precursor. PFOA is considered a surfactant, or fluorosurfactant, due to its chemical structure, which consists of a perfluorinated, ''n''-heptyl "tail group" and a carboxylic acid "head group". The head group can be described as hydrophilic while the fluorocarbon tail is both hydrophobic and lipophobic. The International Agency for Research on Cancer (IARC) has classified PFOA as carcinogenic to humans. PFOA is one of many synthetic organofluorine compounds collectively known as per- and polyfluoroalkyl substances (PFASs). Many PFAS such as Perfluorooctanesulfonic acid, PFOS, PFOA are a concern because they do not break down via natural processes and are commonly described as persistent organic pollutants ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorotelomer Alcohol
Fluorotelomer alcohols, or FTOHs, are fluorotelomers with an alcohol functional group. They are volatile precursors to perfluorinated carboxylic acids, such as PFOA and PFNA, and other compounds. Naming Commonly, an individual fluorotelomer alcohol molecule is named by the number of carbons that are fluorinated versus the number that are hydrocarbon-based. For example, 8:2 fluorotelomer alcohol would represent a molecule with 8 fluorinated carbons and a 2 carbon ethyl alcohol group. The structure of a fluorotelomer alcohol is most commonly F(CF2)nCH2CH2OH, where ''n'' is an even number. Chemistry The synthesis of fluorotelomer alcohols requires a varying number of tetrafluoroethylene monomers that form an oligomer with a pentafluoroethyl iodide telogen. The fluorinated iodide then undergoes an addition with ethylene to form an organoiodine compound with increased synthesis possibilities. The terminal iodine is replaced by a hydroxyl group to yield the fluorotelomer alcohol. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perfluorinated Carboxylic Acid
Perfluoroalkyl carboxylic acids (PFCAs), or perfluorocarboxylic acids are compounds of the formula CnF(2n+1)CO2H that belong to the class of per- and polyfluoroalkyl substances. The simplest example is trifluoroacetic acid. These compounds are organofluorine analogues of ordinary carboxylic acids, but they are stronger by several pKa units and they exhibit great hydrophobic character. Perfluoroalkyl dicarboxylic acids (PFdiCAs) are also known, e.g. C2F4(CO2H)2. Applications Trifluoroacetic acid is a widely employed acid, used for example in the synthesis of peptides. Its esters are useful in analytical chemistry. Longer-chain perfluoroalkyl carboxylic acids, e.g. with five to nine carbons, are useful fluorosurfactants and emulsifiers used in the production of polytetrafluoroethylene (Teflon) and related fluoropolymers. Production These compounds are typically prepared by electrochemical fluorination of the carboxylic acid fluorides followed by hydrolysis: :CnH(2n+1)COF ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telomerization
Telomerization is a reaction that produces a particular kind of oligomer with two distinct end groups. The oligomer is called a telomer. Some telomerizations proceed by radical pathways, many do not. A generic equation is: : where M is the monomer, and A and B are the end groups, and n is the degree of polymerization. One example is the coupled dimerization and hydroesterification of buta-1,3-diene. This step produces a doubly unsaturated C9-ester: :2CH2=CH-CH=CH2 + CO + CH3OH → CH2=CH(CH2)3CH=CHCH2CO2CH3 The monomer in this reaction is butadiene, the degree of polymerization is 2, and the end groups are vinyl and the carboxy methyl (CO2CH3). This and several related reactions proceed with palladium Palladium is a chemical element; it has symbol Pd and atomic number 46. It is a rare and lustrous silvery-white metal discovered in 1802 by the English chemist William Hyde Wollaston. He named it after the asteroid Pallas (formally 2 Pallas), ... catalysts. Many telomeriz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Urethane SCFP Synthesis Simplified
Urethane may refer to: *Ethyl carbamate, a chemical compound which is an ester of carbamic acid *Polyurethane, a polymer composed of a chain of organic units joined by carbamate (urethane) links *Carbamate, an organic compound derived from carbamic acid See also *Acetone Acetone (2-propanone or dimethyl ketone) is an organic compound with the chemical formula, formula . It is the simplest and smallest ketone (). It is a colorless, highly Volatile organic compound, volatile, and flammable liquid with a charact ... * Cetone {{Disambiguation Science disambiguation pages ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acrylate
Acrylates (IUPAC: prop-2-enoates) are the salts, esters, and conjugate bases of acrylic acid. The acrylate ion is the anion . Often, acrylate refers to esters of acrylic acid, the most common member being methyl acrylate. These acrylates contain vinyl groups. These compounds are of interest because they are bifunctional: the vinyl group is susceptible to polymerization and the carboxylate group carries myriad functionalities. Monomers Acrylates are defined by the formula , where R can be many groups: * Acrylic acid * Methyl acrylate * Ethyl acrylate * 2-Chloroethyl vinyl ether * 2-Ethylhexyl acrylate * Butyl acrylate * Trimethylolpropane triacrylate (TMPTA) The versatility of the resulting polymers is owed to the range of R groups. File:Acrylate-anion.svg, The acrylate anion File:Trimethylolpropane triacrylate.svg, Trimethylolpropane triacrylate (TMPTA), a trifunctional acrylate ester File:Methylacrylat.svg, Methyl acrylate, an acrylic ester File:Hexandioldiacrylat.svg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monomer
A monomer ( ; ''mono-'', "one" + '' -mer'', "part") is a molecule that can react together with other monomer molecules to form a larger polymer chain or two- or three-dimensional network in a process called polymerization. Classification Chemistry classifies monomers by type, and two broad classes based on the type of polymer they form. By type: * natural vs synthetic, e.g. glycine vs caprolactam, respectively * polar vs nonpolar, e.g. vinyl acetate vs ethylene, respectively * cyclic vs linear, e.g. ethylene oxide vs ethylene glycol, respectively By type of polymer they form: * those that participate in condensation polymerization * those that participate in addition polymerization Differing stoichiometry causes each class to create its respective form of polymer. : The polymerization of one kind of monomer gives a homopolymer. Many polymers are copolymers, meaning that they are derived from two different monomers. In the case of condensation polymerizations, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
